Gerry, determine what makes your favourite documentaries so engaging. For what you have suggested, find a central character and tell your broad story by telling the story of that lead character so your viewer has someone with whom to identify. Show more than tell. Show how that character has grown or adjusted to their circumstances. If you can, illustrate the path they took to achieve their most important goals even if that is just finding food or putting a child through school or saving a life.
Update* Further to the doc film making learning thingy I have a dinner meeting scheduled at a local restaurant with a man who has decades of documentary film making experience. He is the leader of a local filmmaking group in my city FAVA. Going to meet him this coming tuesday and try to learn!